1. Field of the Invention
The present invention relates generally to a propelling system for use in a boat and more specifically, to a propelling system that can broaden the usable internal space of the boat.
2. Description of the Related Art
FIG. 1 is a schematic drawing showing a propelling system equipped in a small boat 1 according to prior art. The middlebody of hull of the small boat 1 is installed with an engine 110 to which a driving shaft 120 is connected. The driving shaft 120 slantingly downward penetrates through the bottom 130 of a small boat 1 and is supported by an A-shaped frame 140 and then coupled with a propeller 150. Further, the small boat 1 is provided at a stern 160 thereof with a rubber 170.
Because the A-shaped frame 140, the rudder 170 and the propeller 150 are located under the bottom 130 of the small boat 1, these components not only cause relatively higher water drag to reduce the speed of the small boat 1, but also tend to bump a rock or a driftwood accidentally, resulting in damage of themselves. In addition, the engine 110 is generally mounted inside the small boat 1 at the middlebody or afterbody of the boat; therefore, the inside space of the small boat 1 around the middlebody or afterbody area may not be usable for other purpose, i.e. the usable inside space of the small boat 1 is restricted.
FIG. 2 a schematic drawing showing a propelling system equipped in a big yacht 2 according to another prior art. According to this design, the engine 210 is mounted in the middlebody inside the hull of the yacht 2, which limits the utilization of the internal space of the yacht 2, and the propeller 220 and the rudder 270 are located under the bottom of the yacht 2, which may easily hit a rock or hurt divers or the endangered species of marine fauna, such as manatee, or even resulting in that seaweed may be wound on the propeller 220 to be uprooted. Besides, when the yacht 2 would like to sail backward, the yacht 2 has to change its direction through bow thrusters 240 mounted to a bow 230 thereof and stern thrusters 260 mounted to a stern 250 thereof. The mechanisms of the bow thrusters 240 and the stern thrusters 260 will also occupy partial internal space of the yacht 2. Thus, it is desirable to provide a propelling system that eliminates the aforesaid drawbacks.